Enhanced trigger-based null data packet for channel sounding

ABSTRACT

This disclosure describes systems, methods, and devices related to a trigger-based null data packet (NDP) for channel sounding system. A device may send a trigger frame to a group of station devices, the group of station devices including a first station device, the trigger frame indicating a high efficiency (HE) long training field (HE-LTF) mode and a guard interval duration. The device may identify a HE trigger-based (TB) null data packet (NDP) received from the first station device, the HE TB NDP including a first packet extension field, wherein the HE TB NDP is associated with the HE-LTF mode and the guard interval duration indicated in the trigger frame. The device may send a downlink NDP including a second packet extension field, a second HE-LTF mode, and a second guard interval duration. The device may determine channel state information based on HE TB NDP received from the first station device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Non-Provisional applicationSer. No. 16/234,217, filed Dec. 26, 2018, which claims the benefit ofU.S. Provisional Application No. 62/629,966, filed Feb. 13, 2018, bothdisclosures of which is incorporated by reference as if set forth infull.

TECHNICAL FIELD

This disclosure generally relates to systems, methods, and devices forwireless communications and, more particularly, trigger-based null datapacket (NDP) for channel sounding.

BACKGROUND

Wireless devices are becoming widely prevalent and are increasinglyrequesting access to wireless channels. Wireless devices may benefitfrom evaluating wireless channels.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a diagram illustrating an example network environment, inaccordance with one or more example embodiments of the presentdisclosure.

FIG. 2A depicts an illustrative multi-user measurement sequence, inaccordance with one or more example embodiments of the presentdisclosure.

FIG. 2B depicts an illustrative high-efficiency sounding null datapacket, in accordance with one or more example embodiments of thepresent disclosure.

FIG. 2C depicts an illustrative high-efficiency trigger-based null datapacket, in accordance with one or more example embodiments of thepresent disclosure.

FIG. 3A depicts an illustrative enhanced high-efficiency trigger-basednull data packet, in accordance with one or more example embodiments ofthe present disclosure.

FIG. 3B depicts an illustrative single user measurement sequence, inaccordance with one or more example embodiments of the presentdisclosure.

FIG. 4A depicts a flow diagram of illustrative process for channelsounding using a trigger-based NDP, in accordance with one or moreembodiments of the disclosure.

FIG. 4B depicts a flow diagram of illustrative process for channelsounding using a trigger-based NDP, in accordance with one or moreembodiments of the disclosure.

FIG. 5 depicts a functional diagram of an example communication station,in accordance with one or more example embodiments of the presentdisclosure.

FIG. 6 depicts a block diagram of an example machine upon which any ofone or more techniques (e.g., methods) may be performed, in accordancewith one or more example embodiments of the present disclosure.

DETAILED DESCRIPTION

Example embodiments described herein provide certain systems, methods,and devices, for trigger-based null data packet (NDP) for channelsounding.

The following description and the drawings sufficiently illustratespecific embodiments to enable those skilled in the art to practicethem. Other embodiments may incorporate structural, logical, electrical,process, and other changes. Portions and features of some embodimentsmay be included in, or substituted for, those of other embodiments.Embodiments set forth in the claims encompass all available equivalentsof those claims.

In wireless communications, devices may use a variety of methods todetermine a device's location/position. For example, devices mayexchange data transmissions using a null data packet (NDP) withsequences of symbols. A portion of an NDP frame may include one or moresounding symbols. Each sounding symbol may have a set of subcarriers(e.g., tones) having non-zero energy, and some guard subcarriers such asdirect current (DC) subcarriers and edge subcarriers. Based on thesymbols in a sounding signal, devices may perform time of arrivalestimation (e.g., a time of arrival of a sounding signal at a device),which may be used to determine device's range respective to otherdevices.

Channel sounding may allow devices to determine the quality and behaviorof wireless communication mediums (e.g., channels and/or frequencybands). In a basic channel sounding process, a transmitter may send asequence to a receiver. The receiver may receive the sequence and, basedon the transmitted sequence, may determine an impulse response of achannel between the transmitter and receiver. Due to the effect of anenvironment (e.g., an area with many people, buildings, objects, etc.),wireless signals may travel in multiple paths between a transmitter andreceiver. The paths may be affected by reflection, refraction,scattering, and other factors, which may result in multiple versions ofa signal arriving at a receiver at different times. To perform channelsounding, a frame format which uses an entire frequency band may bedefined.

In an MU measurement sequence, such as in the IEEE 802.11az Wi-Ficommunications standard, a responder (e.g., access point device) maysend a trigger frame to solicit uplink (UL) transmissions of soundingframes (e.g., null data packets) from initiators (e.g., stationdevices). However, the frame format of the UL sounding null data packet(NDP) is not defined yet for MU communications, so initiators in MUsounding operations may not be able to respond to a trigger framerequesting an uplink transmission for use in channel sounding.

Some existing NDP frame formats have been defined, such as a highefficiency (HE) sounding NDP physical layer convergence protocol dataunit (PPDU) and a HE trigger-based (TB) NDP feedback PPDU (e.g., asdefined in the IEEE 802.11 standards for Wi-Fi communications). The HEsounding NDP PPDU may be used for beamforming purposes in which devicestrain their respective antennas directionally. For example, after abeamformee device receives a HE sounding NDP, the beamformee mayestimate a channel used to send the HE sounding NDP by analyzing theNDP. The analysis may include determining channel state information(CSI). The beamformee device may send the CSI information to abeamformer which sent the HE sounding NDP. The HE NDP PPDU may supportmultiple HE long training field (HE-LTF) modes and guard intervals. TheHE NDP PPDU may include a HE-LTF whose duration is based on an LTFsymbol of the HE NDP PPDU and the HE-LTF mode. The guard intervaldurations supported by the HE NDP PPDU may include 0.8 us, 1.6 us, 3.2us, and other durations. The HE NDP PPDU may indicate combinations ofHE-LTF modes and guard interval durations, for example, using a HEsignal-A (HE-SIG-A) field.

A trigger frame sent by an access point (AP) may cause a station device(STA) to send one or more uplink transmissions to the AP, such as a HETB NDP feedback PPDU. A trigger frame may indicate combinations ofHE-LTF modes and guard interval durations. A STA may transmit usingassigned tone sets (e.g., frequency tones associated with allocatedresource units in a channel/band) to indicate whether the STA has packetin a queue and requests a resource for from an AP for uplinktransmission.

However, neither of the above two types of NDPs may be used for theuplink channel sounding because the HE TB NDP feedback PPDU only usessome tones rather than the entire frequency band, and because the HEsounding NDP PPDU is formatted for downlink transmissions and does notprovide a long enough HE short training field (HE-STF) for uplinksounding operations.

In particular, if the existing HE sounding NDP PPDU were to be used forMU UL sounding operations, the HE-STF may not allow for proper channelsounding because the HE-STF of the HE sounding NDP PPDU may be 4 us, andMU UL sounding operations may need a longer time (e.g., 8 us) for theHE-STF so that, for example, an AP may receive a UL PPDU and havesufficient information to determine automatic gain control. In addition,the HE sounding NDP PPDU may not have a way to indicate that it is beingused for UL sounding. The existing HE TB NDP feedback PPDU may notsupport a 2xLTF (2x long training field) mode with a duration of 1.6 us,and may be limited to a packet extension of zero when UL sounding maybenefit from using both 2xLTF modes, with guard interval durations of1.6 us, and from using other packet extension lengths. Also, the HE TBNDP feedback PPDU may use an allocated tone set within a frequency band,which may not include the entire band, and therefore the channelsounding using this type of PPDU may not allow for measurements of anentire channel/band.

Therefore, to ease implementation for sounding an entire channel/band,parts of the HE sounding NDP PPDU and the HE TB NDP feedback PPDU may beused to create a TB NDP PPDU for UL channel sounding, with somemodifications. By reusing portions of the existing formats, the newframe format for UL sounding may be compatible with existing and newdevices.

Example embodiments of the present disclosure relate to systems,methods, and devices for trigger-based NDP for channel sounding.

In one embodiment, a Trigger-based NDP for channel sounding system maydefine an enhanced frame format for the UL NDP. The enhanced frameformat is compatible with the NDP frame format in the current 802.11axstandard. In particular, the enhanced frame format may use a portion ofa HE sounding NDP PPDU, but the parameter fields in the HE signature-A(HE-SIG-A) field of the HE sounding NDP PPDU may be set according to aformat of a HE-SIG-A field of a HE TB PPDU. The enhanced frame formatmay use an entire channel or band like the HE sounding NDP PPDU, butmodified for an uplink format partially based on the HE sounding NDPPPDU.

In one embodiment, when performing a single user (SU) channelmeasurement sequence, an initiator device and a responder device maysend a HE sounding NDP PPDU to one another, but when the responder sendsa HE sounding NDP PPDU, the responder may set a bit (e.g., bit BO) of aHE-SIG-A1 field to zero to indicate that the HE sounding NDP PPDU is aHE TB PPDU.

The above descriptions are for purposes of illustration and are notmeant to be limiting. Numerous other examples, configurations,processes, etc., may exist, some of which are described in detail below.Example embodiments will now be described with reference to theaccompanying figures.

FIG. 1 is a diagram illustrating an example network environment, inaccordance with one or more example embodiments of the presentdisclosure. Wireless network 100 may include one or more user devices120 and one or more access point(s) (AP) 102, which may communicate inaccordance with IEEE 802.11 communication standards. The user device(s)120 may be mobile devices that are non-stationary (e.g., not havingfixed locations) or may be stationary devices.

In some embodiments, the user devices 120, and the AP(s) 102 may includeone or more computer systems similar to that of the functional diagramof FIG. 5 and/or the example machine/system of FIG. 6.

One or more illustrative user device(s) 120 and/or AP(s) 102 may beoperable by one or more user(s) 110. It should be noted that anyaddressable unit may be a station (STA). An STA may take on multipledistinct characteristics, each of which shape its function. For example,a single addressable unit might simultaneously be a portable STA, aquality-of-service (QoS) STA, a dependent STA, and a hidden STA. The oneor more illustrative user device(s) 120 and the AP(s) 102 may be STAs.The one or more illustrative user device(s) 120 and/or AP(s) 102 mayoperate as a personal basic service set (PBSS) control point/accesspoint (PCP/AP). The user device(s) 120 (e.g., 124, 126, or 128) and/orAP(s) 102 may include any suitable processor-driven device including,but not limited to, a mobile device or a non-mobile, e.g., a static,device. For example, user device(s) 120 and/or AP(s) 102 may include, auser equipment (UE), a station (STA), an access point (AP), a softwareenabled AP (SoftAP), a personal computer (PC), a wearable wirelessdevice (e.g., bracelet, watch, glasses, ring, etc.), a desktop computer,a mobile computer, a laptop computer, an Ultrabook™ computer, a notebookcomputer, a tablet computer, a server computer, a handheld computer, ahandheld device, an internet of things (IoT) device, a sensor device, aPDA device, a handheld PDA device, an on-board device, an off-boarddevice, a hybrid device (e.g., combining cellular phone functionalitieswith PDA device functionalities), a consumer device, a vehicular device,a non-vehicular device, a mobile or portable device, a non-mobile ornon-portable device, a mobile phone, a cellular telephone, a PCS device,a PDA device which incorporates a wireless communication device, amobile or portable GPS device, a DVB device, a relatively smallcomputing device, a non-desktop computer, a “carry small live large”(CSLL) device, an ultra mobile device (UMD), an ultra mobile PC (UMPC),a mobile internet device (MID), an “origami” device or computing device,a device that supports dynamically composable computing (DCC), acontext-aware device, a video device, an audio device, an A/V device, aset-top-box (STB), a blu-ray disc (BD) player, a BD recorder, a digitalvideo disc (DVD) player, a high definition (HD) DVD player, a DVDrecorder, a HD DVD recorder, a personal video recorder (PVR), abroadcast HD receiver, a video source, an audio source, a video sink, anaudio sink, a stereo tuner, a broadcast radio receiver, a flat paneldisplay, a personal media player (PMP), a digital video camera (DVC), adigital audio player, a speaker, an audio receiver, an audio amplifier,a gaming device, a data source, a data sink, a digital still camera(DSC), a media player, a smartphone, a television, a music player, orthe like. Other devices, including smart devices such as lamps, climatecontrol, car components, household components, appliances, etc. may alsobe included in this list.

As used herein, the term “Internet of Things (IoT) device” is used torefer to any object (e.g., an appliance, a sensor, etc.) that has anaddressable interface (e.g., an Internet protocol (IP) address, aBluetooth identifier (ID), a near-field communication (NFC) ID, etc.)and can transmit information to one or more other devices over a wiredor wireless connection. An IoT device may have a passive communicationinterface, such as a quick response (QR) code, a radio-frequencyidentification (RFID) tag, an NFC tag, or the like, or an activecommunication interface, such as a modem, a transceiver, atransmitter-receiver, or the like. An IoT device can have a particularset of attributes (e.g., a device state or status, such as whether theIoT device is on or off, open or closed, idle or active, available fortask execution or busy, and so on, a cooling or heating function, anenvironmental monitoring or recording function, a light-emittingfunction, a sound-emitting function, etc.) that can be embedded inand/or controlled/monitored by a central processing unit (CPU),microprocessor, ASIC, or the like, and configured for connection to anIoT network such as a local ad-hoc network or the Internet. For example,IoT devices may include, but are not limited to, refrigerators,toasters, ovens, microwaves, freezers, dishwashers, dishes, hand tools,clothes washers, clothes dryers, furnaces, air conditioners,thermostats, televisions, light fixtures, vacuum cleaners, sprinklers,electricity meters, gas meters, etc., so long as the devices areequipped with an addressable communications interface for communicatingwith the IoT network. IoT devices may also include cell phones, desktopcomputers, laptop computers, tablet computers, personal digitalassistants (PDAs), etc. Accordingly, the IoT network may be comprised ofa combination of “legacy” Internet-accessible devices (e.g., laptop ordesktop computers, cell phones, etc.) in addition to devices that do nottypically have Internet-connectivity (e.g., dishwashers, etc.).

The user device(s) 120 and/or AP(s) 102 may also include mesh stationsin, for example, a mesh network, in accordance with one or more IEEE802.11 standards and/or 3GPP standards.

Any of the user device(s) 120 (e.g., user devices 124, 126, 128), andAP(s) 102 may be configured to communicate with each other via one ormore communications networks 130 and/or 135 wirelessly or wired. Theuser device(s) 120 may also communicate peer-to-peer or directly witheach other with or without the AP(s) 102. Any of the communicationsnetworks 130 and/or 135 may include, but not limited to, any one of acombination of different types of suitable communications networks suchas, for example, broadcasting networks, cable networks, public networks(e.g., the Internet), private networks, wireless networks, cellularnetworks, or any other suitable private and/or public networks. Further,any of the communications networks 130 and/or 135 may have any suitablecommunication range associated therewith and may include, for example,global networks (e.g., the Internet), metropolitan area networks (MANs),wide area networks (WANs), local area networks (LANs), or personal areanetworks (PANs). In addition, any of the communications networks 130and/or 135 may include any type of medium over which network traffic maybe carried including, but not limited to, coaxial cable, twisted-pairwire, optical fiber, a hybrid fiber coaxial (HFC) medium, microwaveterrestrial transceivers, radio frequency communication mediums, whitespace communication mediums, ultra-high frequency communication mediums,satellite communication mediums, or any combination thereof.

Any of the user device(s) 120 (e.g., user devices 124, 126, 128) andAP(s) 102 may include one or more communications antennas. The one ormore communications antennas may be any suitable type of antennascorresponding to the communications protocols used by the user device(s)120 (e.g., user devices 124, 126 and 128), and AP(s) 102. Somenon-limiting examples of suitable communications antennas include Wi-Fiantennas, Institute of Electrical and Electronics Engineers (IEEE)802.11 family of standards compatible antennas, directional antennas,non-directional antennas, dipole antennas, folded dipole antennas, patchantennas, multiple-input multiple-output (MIMO) antennas,omnidirectional antennas, quasi-omnidirectional antennas, or the like.The one or more communications antennas may be communicatively coupledto a radio component to transmit and/or receive signals, such ascommunications signals to and/or from the user devices 120 and/or AP(s)102.

Any of the user device(s) 120 (e.g., user devices 124, 126, 128), andAP(s) 102 may be configured to perform directional transmission and/ordirectional reception in conjunction with wirelessly communicating in awireless network. Any of the user device(s) 120 (e.g., user devices 124,126, 128), and AP(s) 102 may be configured to perform such directionaltransmission and/or reception using a set of multiple antenna arrays(e.g., DMG antenna arrays or the like). Each of the multiple antennaarrays may be used for transmission and/or reception in a particularrespective direction or range of directions. Any of the user device(s)120 (e.g., user devices 124, 126, 128), and AP(s) 102 may be configuredto perform any given directional transmission towards one or moredefined transmit sectors. Any of the user device(s) 120 (e.g., userdevices 124, 126, 128), and AP(s) 102 may be configured to perform anygiven directional reception from one or more defined receive sectors.

MIMO beamforming in a wireless network may be accomplished using RFbeamforming and/or digital beamforming. In some embodiments, inperforming a given MIMO transmission, user devices 120 and/or AP(s) 102may be configured to use all or a subset of its one or morecommunications antennas to perform MIMO beamforming.

Any of the user devices 120 (e.g., user devices 124, 126, 128), andAP(s) 102 may include any suitable radio and/or transceiver fortransmitting and/or receiving radio frequency (RF) signals in thebandwidth and/or channels corresponding to the communications protocolsutilized by any of the user device(s) 120 and AP(s) 102 to communicatewith each other. The radio components may include hardware and/orsoftware to modulate and/or demodulate communications signals accordingto pre-established transmission protocols. The radio components mayfurther have hardware and/or software instructions to communicate viaone or more Wi-Fi and/or Wi-Fi direct protocols, as standardized by theInstitute of Electrical and Electronics Engineers (IEEE) 802.11standards.

Some embodiments may be used in conjunction with devices and/or networksoperating in accordance with existing. Wireless Fidelity (Wi-Fi)Alliance (WFA) Specifications, including Wi-Fi Neighbor AwarenessNetworking (NAN) Technical Specification (e.g., NAN and NAN2) and/orfuture versions and/or derivatives thereof, devices and/or networksoperating in accordance with existing WFA Peer-to-Peer (P2P)specifications and/or future versions and/or derivatives thereof,devices and/or networks operating in accordance with existingWireless-Gigabit-Alliance (WGA) specifications (Wireless GigabitAlliance, Inc. WiGig MAC and PHY Specification) and/or future versionsand/or derivatives thereof, devices and/or networks operating inaccordance with existing IEEE 802.11 standards and/or amendments (e.g.,802.11b, 802.11g, 802.11n, 802.11ac, 802.11ax, 802.11ad, 802.11ay,802.11az, etc.).

In certain example embodiments, the radio component, in cooperation withthe communications antennas, may be configured to communicate via 2.4GHz channels (e.g., 802.11b, 802.11g, 802.11n, 802.11ax), 5 GHz channels(e.g., 802.11n, 802.11ac, 802.11ax), or 60 GHZ channels (e.g.,802.11ad). In some embodiments, non-Wi-Fi protocols may be used forcommunications between devices, such as Bluetooth, dedicated short-rangecommunication (DSRC), Ultra-High Frequency (UHF) (e.g., IEEE 802.11af,IEEE 802.22), white band frequency (e.g., white spaces), or otherpacketized radio communications. The radio component may include anyknown receiver and baseband suitable for communicating via thecommunications protocols. The radio component may further include a lownoise amplifier (LNA), additional signal amplifiers, ananalog-to-digital (A/D) converter, one or more buffers, and digitalbaseband.

In one embodiment, and with reference to FIG. 1, a user device 120 maybe in communication with one or more APs 102.

For example, one or more APs 102 may perform MU channel sounding or SUchannel sounding with the user device(s) 120. The one or more APs 102and the user device(s) 120 may exchange packets 140. The packets 140 mayinclude trigger frames, HE NDP PPDUs, HE trigger-based NDP feedbackPPDUs, enhanced HE trigger-based PPDUs, NDP announcement (NDPA) frames,channel information/measurement feedback frames, and other frames whichmay facilitate channel sounding operations.

FIG. 2A depicts an illustrative multi-user measurement sequence 200, inaccordance with one or more example embodiments of the presentdisclosure.

Referring to FIG. 2A, the sequence 200 may include a MU measurementsequence such as defined by the IEEE 802.11az communication standard. Aresponder AP 202 may perform sounding operations with a first group ofinitiators (e.g., initiator 204, initiator 206) and a second group ofinitiators (e.g., initiator 208, initiator 210). The responder AP maysend a trigger frame 212 to solicit UL sounding NDPs from the firstgroup of initiators. For example, the trigger frame 212 may identify thefirst group of initiators. The initiator 204 may send a UL NDP 214 tothe responder AP 202. The initiator 206 may send a UL NDP 216 to theresponder AP 202. The responder AP 202 may send a trigger frame 218addressed to the second group of initiators. The initiator 208 may senda UL NDP 220 to the responder AP 202. The initiator 210 may send a ULNDP 222 to the responder AP 202. The responder AP 202 may sendadditional trigger frames to other groups of initiators and may receiverespective UL NDPs in response. After the initiators have sent UL NDPstriggered by trigger frames sent by the responder AP 202, the responderAP 202 may send an NDPA 224 indicating a subsequent transmission, andsubsequently may send a NDP 226.

The trigger frames sent by the responder AP 202 may indicate that theyare trigger frames for UL NDPs so that the initiators provide the ULNDPs to the responder AP 202. The NDP 226 may use a frame format for aHE NDP PPDU, however, the frame format for the UL NDPs may need to bedefined and enhanced to allow a longer HE-STF field for sounding, and tosupport multiple HE-LTF modes and guard interval durations.

The MU measurement sequence 200 may be completed within a singletransmission opportunity (TXOP). For example, after any frame is sent,the AP 202 and any of the user devices may wait a time, such as a shortinter-frame space (SIFS) 230, before sending a subsequent frame.

FIG. 2B depicts an illustrative HE sounding NDP 240, in accordance withone or more example embodiments of the present disclosure.

Referring to FIG. 2B, the HE sounding NDP 240 may include one or morefields, such as a legacy short training field (L-STF) 242, a legacy longtraining field (L-LTF) 244, a legacy signal field (L-SIG) 246, arepeated legacy signal field (RL-SIG) 248, a HE-SIG-A field 250, a HEshort training field (HE-STF) 252, a HE long training field (HE-LTF)254, and a packet extension (PE) field 256. The L-STF field 242 may havea length of 8 us. The L-LTF field 244 may have a duration of 8 us. TheL-SIG field 246 may have a duration of 4 us. The RL-SIG field 248 mayhave a duration of 4 us. The HE-SIG-A field 250 may have a duration of 8us. The HE-STF field 252 may have a duration of 4 us. The HE-LTF field254 may have a duration of 7.2 us or 8 us per HE-LTF symbol when using a2x HE-LTF mode, and may have a duration of 16 us per HE-LTF symbol whenusing a 4x HE-LTF mode. The PE field 256 may have a duration of 4 us.

NDP may be a HE sounding format. The number of HE-LTF symbols in the HEsounding NDP 240 may be determined by a sub-field of the HE-SIG-A field250 indicating a number of spatial streams (e.g., allocated to one ormore users). The HE sounding NDP 240 may use a HE SU PPDU format, butwithout a data field, and may use the PE field 256 of 4 us. The HEsounding NDP 240 may support a 2x HE-LTF mode with a guard interval of0.8 us, a 2x HE-LTF mode with a guard interval of 1.6 us, and a 4xHE-LTF mode with a guard interval of 3.2 us.

FIG. 2C depicts an illustrative HE trigger-based NDP 260, in accordancewith one or more example embodiments of the present disclosure.

Referring to FIG. 2C, the HE trigger-based NDP 260 may include one ormore fields, such as a legacy short training field (L-STF) 262, a legacylong training field (L-LTF) 264, a legacy signal field (L-SIG) 266, arepeated legacy signal field (RL-SIG) 268, a HE-SIG-A field 270, a HEshort training field (HE-STF) 272, and a HE long training field (HE-LTF)274. The L-STF field 262 may have a length of 8 us. The L-LTF field 264may have a duration of 8 us. The L-SIG field 266 may have a duration of4 us. The RL-SIG field 268 may have a duration of 4 us. The HE-SIG-Afield 270 may have a duration of 8 us. The HE-STF field 272 may have aduration of 8 us. The HE-LTF field 274 may have a duration based on twoHE-LTF symbols with 16 us per symbol using the 4x HE-LTF mode.

The HE trigger-based NDP 260 may include NDP feedback reportinformation. The HE trigger-based NDP 260 may use a HE trigger-basedPPDU format without a data field and with a PE duration of zero (e.g.,no PE field). The HE trigger-based NDP 260 may have two 4x HE-LTF modesymbols, and may support only the 4x HE-LTF mode and guard intervalduration.

FIG. 3A depicts an illustrative enhanced HE trigger-based NDP 300, inaccordance with one or more example embodiments of the presentdisclosure.

Referring to FIG. 3A, the enhanced HE trigger-based NDP 300 may includeone or more fields, such as a legacy short training field (L-STF) 302, alegacy long training field (L-LTF) 304, a legacy signal field (L-SIG)306, a repeated legacy signal field (RL-SIG) 308, a HE-SIG-A field 310,a HE short training field (HE-STF) 312, a HE long training field(HE-LTF) 314, and a packet extension (PE) field 316. The L-STF field 302may have a length of 8 us. The L-LTF field 323040 may have a duration of8 us. The L-SIG field 306 may have a duration of 4 us. The RL-SIG field308 may have a duration of 4 us. The HE-SIG-A field 310 may have aduration of 8 us. The HE-STF field 312 may have a duration of 8 us. TheHE-LTF field 314 may have a duration of 7.2 us or 8 us per HE-LTF symbolwhen using a 2x HE-LTF mode, and may have a duration of 16 us per HE-LTFsymbol when using a 4x HE-LTF mode. The PE field 256 may have a durationof 0, 4, 8, 12, or 16 us, or another duration.

The enhanced HE trigger-based NDP 300 may use the same frame structure(e.g., the same fields) as the HE sounding NDP 240 of FIG. 2B, howeverthe duration of the HE-STF field 312 may have a duration of 8 us, andparameters of the HE-SIG-A field 310 may be different from parameters ofthe HE-SIG-A field 250 of FIG. 2B, and may be based on the HE-SIG-Afield 270 of the HE trigger-based NDP 260 of FIG. 2C. Unlike the HEtrigger-based NDP 260 of FIG. 2C, the enhanced HE trigger-based NDP 300may include a PE field (e.g., PE field 316), which may be longer thanzero.

The enhanced HE trigger-based NDP 300 may support the 2x HE-LTF modewith a guard interval duration of 0.8 us, the 2x HE-LTF mode with aguard interval duration of 1.6 us, and the 4x HE-LTF mode with a guardinterval duration of 3.2 us. Thus, the enhanced HE trigger-based NDP 300may enhance the HE trigger-based NDP 260 by supporting additional HE-LTFmodes and including a PE.

FIG. 3B depicts an illustrative SU measurement sequence 350, inaccordance with one or more example embodiments of the presentdisclosure.

Referring to FIG. 3B, the SU measurement sequence 350 may include aninitiator STA 352 and a responder STA 354. The initiator STA 352 maysend an NDPA 356 to announce the transmission of a NDP 358, and after aSIFS 370 time of sending the NDPA 356, the initiator STA 352 may sendthe NDP 358. The responder STA 354 may send a NDP 360 after SIFS 370time of receiving the NDP 358, and after SIFS 370 time of sending theNDP 360, the responder STA 354 may send measurement feedback 362 to theinitiator STA 352. The measurement feedback 362 may include a time ofarrival of the NDP 358 and a time of departure of the NDP 360 that theinitiator STA 352 may use to measure a distance/range to the responderSTA 354.

The NDP 358 may use the format of the HE sounding NDP 240 of FIG. 2B.The NDP 360 may use the format of the HE sounding NDP 240 of FIG. 2B,and may include a first bit (e.g., bit BO) set by the responder STA 354to zero to indicate that the NDP 360 is a HE TB PPDU.

The SU measurement sequence 350 may be completed within a single TXOP.For example, after any frame is sent, a device may wait a time, such asSIFS 370, before sending another frame.

FIG. 4A depicts a flow diagram of illustrative process 400 for channelsounding using a trigger-based NDP, in accordance with one or moreexample embodiments of the present disclosure.

At block 402, a device (e.g., the AP 102 of FIG. 1) may send a triggerframe to a group of station devices, the group of station devicesincluding a first station device, the trigger frame including a firstindication of a HE-LTF mode and a second indication of a guard intervalduration. The HE-LTF mode may be a 2x HE-LTF mode or a 4x HE-LTF mode.The guard interval duration may be 0.8 microseconds, 1.6 microseconds,or 3.2 microseconds.

At block 404, the device may identify a HE TB NDP received from thefirst station device, the HE TB NDP including a first packet extensionfield, and the HE TB NDP being associated with the HE-LTF mode and theguard interval duration. The packet extension field may have a durationof 0, 4, 8, 12, 16, or another number of microseconds. The HE TB NDP maysupport a 2x HE-LTF mode or a 4x HE-LTF mode.

At block 406, the device may determine channel state information basedon the HE TB NDP received from the first station device. Channel stateinformation may be determined by a receiving device and sent to thetransmitting device, and the devices may use the channel stateinformation to derive the time of arrival of the corresponding HE TBNDP.

At block 408, the device may send a downlink NDPA frame. The NDPA framemay indicate that the device may send a NDP frame after a time, such asSIFS.

At block 410, the device may send a downlink NDP, wherein the downlinkNDP includes a second packet extension field. The downlink NDP may be aHE sounding NDP, and may support a 2x HE-LTF mode or a 4x HE-LTF mode.The packet extension field of the downlink NDP may have a duration of 4microseconds.

FIG. 4B depicts a flow diagram of illustrative process 450 for channelsounding using a trigger-based NDP, in accordance with one or moreexample embodiments of the present disclosure.

At block 452, a device (e.g., the user device 120 of FIG. 1) mayidentify a trigger frame received from an AP (e.g., a respondingdevice). The trigger frame may include a first indication of a HE-LTFmode and a second indication of a guard interval duration. The HE-LTFmode may be a 2x HE-LTF mode or a 4x HE-LTF mode. The guard intervalduration may be 0.8 microseconds, 1.6 microseconds, or 3.2 microseconds.

At block 454, the device may determine, based on the trigger frame, aHE-LTF mode and a guard interval duration. For example, the HE-LTF modemay be a 2x HE-LTF mode with a guard interval duration of 0.8microseconds or a guard interval duration of 1.6 microseconds. TheHE-LTF mode may be a 4x HE-LTF mode with a guard interval duration of3.2 microseconds.

At block 456, the device may determine, based on the HE-LTF mode and theguard interval duration, a HE TB NDP, the HE TB NDP including a firstpacket extension field. The packet extension field may have a durationof 0, 4, 8, 12, 16, or another number of microseconds. The packetextension field may support a 2x HE-LTF mode or a 4x HE-LTF mode.

At block 458, the device may send the HE TB NDP to the AP.

At block 460, the device may identify a downlink NDPA frame receivedfrom the AP. The NDPA frame may indicate that the AP may send asubsequent NDP frame.

At block 462, the device may identify a downlink NDP received from theAP, the downlink NDP including a second packet extension field. Thepacket extension field may have a duration of 4 microseconds. Thedownlink NDP may be a HE sounding NDP, and may support a 2x HE-LTF modeor a 4x HE-LTF mode.

At block 464, the device may determine, based on the downlink NDP,channel state information.

It is understood that the above descriptions are for purposes ofillustration and are not meant to be limiting.

FIG. 5 shows a functional diagram of an exemplary communication station500 in accordance with some embodiments. In one embodiment, FIG. 5illustrates a functional block diagram of a communication station thatmay be suitable for use as an AP 102 (FIG. 1) or user device 120(FIG. 1) in accordance with some embodiments. The communication station500 may also be suitable for use as a handheld device, a mobile device,a cellular telephone, a smartphone, a tablet, a netbook, a wirelessterminal, a laptop computer, a wearable computer device, a femtocell, ahigh data rate (HDR) subscriber station, an access point, an accessterminal, or other personal communication system (PCS) device.

The communication station 500 may include communications circuitry 502and a transceiver 510 for transmitting and receiving signals to and fromother communication stations using one or more antennas 501. Thetransceiver 510 may be a device comprising both a transmitter and areceiver that are combined and share common circuitry (e.g.,communication circuitry 502). The communication circuitry 502 mayinclude amplifiers, filters, mixers, analog to digital and/or digital toanalog converters. The transceiver 510 may transmit and receive analogor digital signals. The transceiver 510 may allow reception of signalsduring transmission periods. This mode is known as full-duplex, and mayrequire the transmitter and receiver to operate on different frequenciesto minimize interference between the transmitted signal and the receivedsignal. The transceiver 510 may operate in a half-duplex mode, where thetransceiver 510 may transmit or receive signals in one direction at atime.

The communications circuitry 502 may include circuitry that can operatethe physical layer (PHY) communications and/or media access control(MAC) communications for controlling access to the wireless medium,and/or any other communications layers for transmitting and receivingsignals. The communication station 500 may also include processingcircuitry 506 and memory 508 arranged to perform the operationsdescribed herein. In some embodiments, the communications circuitry 502and the processing circuitry 506 may be configured to perform operationsdetailed in detailed in FIGS. 1-4.

In accordance with some embodiments, the communications circuitry 502may be arranged to contend for a wireless medium and configure frames orpackets for communicating over the wireless medium. The communicationscircuitry 502 may be arranged to transmit and receive signals. Thecommunications circuitry 502 may also include circuitry formodulation/demodulation, upconversion/downconversion, filtering,amplification, etc. In some embodiments, the processing circuitry 506 ofthe communication station 500 may include one or more processors. Inother embodiments, two or more antennas 501 may be coupled to thecommunications circuitry 502 arranged for sending and receiving signals.The memory 508 may store information for configuring the processingcircuitry 506 to perform operations for configuring and transmittingmessage frames and performing the various operations described herein.The memory 508 may include any type of memory, including non-transitorymemory, for storing information in a form readable by a machine (e.g., acomputer). For example, the memory 508 may include a computer-readablestorage device, read-only memory (ROM), random-access memory (RAM),magnetic disk storage media, optical storage media, flash-memory devicesand other storage devices and media.

In some embodiments, the communication station 500 may be part of aportable wireless communication device, such as a personal digitalassistant (PDA), a laptop or portable computer with wirelesscommunication capability, a web tablet, a wireless telephone, asmartphone, a wireless headset, a pager, an instant messaging device, adigital camera, an access point, a television, a medical device (e.g., aheart rate monitor, a blood pressure monitor, etc.), a wearable computerdevice, or another device that may receive and/or transmit informationwirelessly.

In some embodiments, the communication station 500 may include one ormore antennas 501. The antennas 501 may include one or more directionalor omnidirectional antennas, including, for example, dipole antennas,monopole antennas, patch antennas, loop antennas, microstrip antennas,or other types of antennas suitable for transmission of RF signals. Insome embodiments, instead of two or more antennas, a single antenna withmultiple apertures may be used. In these embodiments, each aperture maybe considered a separate antenna. In some multiple-input multiple-output(MIMO) embodiments, the antennas may be effectively separated forspatial diversity and the different channel characteristics that mayresult between each of the antennas and the antennas of a transmittingstation.

In some embodiments, the communication station 500 may include one ormore of a keyboard, a display, a non-volatile memory port, multipleantennas, a graphics processor, an application processor, speakers, andother mobile device elements. The display may be an LCD screen includinga touch screen.

Although the communication station 500 is illustrated as having severalseparate functional elements, two or more of the functional elements maybe combined and may be implemented by combinations ofsoftware-configured elements, such as processing elements includingdigital signal processors (DSPs), and/or other hardware elements. Forexample, some elements may include one or more microprocessors, DSPs,field-programmable gate arrays (FPGAs), application specific integratedcircuits (ASICs), radio-frequency integrated circuits (RFICs) andcombinations of various hardware and logic circuitry for performing atleast the functions described herein. In some embodiments, thefunctional elements of the communication station 500 may refer to one ormore processes operating on one or more processing elements.

Certain embodiments may be implemented in one or a combination ofhardware, firmware, and software. Other embodiments may also beimplemented as instructions stored on a computer-readable storagedevice, which may be read and executed by at least one processor toperform the operations described herein. A computer-readable storagedevice may include any non-transitory memory mechanism for storinginformation in a form readable by a machine (e.g., a computer). Forexample, a computer-readable storage device may include read-only memory(ROM), random-access memory (RAM), magnetic disk storage media, opticalstorage media, flash-memory devices, and other storage devices andmedia. In some embodiments, the communication station 500 may includeone or more processors and may be configured with instructions stored ona computer-readable storage device memory.

FIG. 6 illustrates a block diagram of an example of a machine 600 orsystem upon which any one or more of the techniques (e.g.,methodologies) discussed herein may be performed. In other embodiments,the machine 600 may operate as a standalone device or may be connected(e.g., networked) to other machines. In a networked deployment, themachine 600 may operate in the capacity of a server machine, a clientmachine, or both in server-client network environments. In an example,the machine 600 may act as a peer machine in peer-to-peer (P2P) (orother distributed) network environments. The machine 600 may be apersonal computer (PC), a tablet PC, a set-top box (STB), a personaldigital assistant (PDA), a mobile telephone, a wearable computer device,a web appliance, a network router, a switch or bridge, or any machinecapable of executing instructions (sequential or otherwise) that specifyactions to be taken by that machine, such as a base station. Further,while only a single machine is illustrated, the term “machine” shallalso be taken to include any collection of machines that individually orjointly execute a set (or multiple sets) of instructions to perform anyone or more of the methodologies discussed herein, such as cloudcomputing, software as a service (SaaS), or other computer clusterconfigurations.

Examples, as described herein, may include or may operate on logic or anumber of components, modules, or mechanisms. Modules are tangibleentities (e.g., hardware) capable of performing specified operationswhen operating. A module includes hardware. In an example, the hardwaremay be specifically configured to carry out a specific operation (e.g.,hardwired). In another example, the hardware may include configurableexecution units (e.g., transistors, circuits, etc.) and a computerreadable medium containing instructions where the instructions configurethe execution units to carry out a specific operation when in operation.The configuring may occur under the direction of the executions units ora loading mechanism. Accordingly, the execution units arecommunicatively coupled to the computer-readable medium when the deviceis operating. In this example, the execution units may be a member ofmore than one module. For example, under operation, the execution unitsmay be configured by a first set of instructions to implement a firstmodule at one point in time and reconfigured by a second set ofinstructions to implement a second module at a second point in time.

The machine (e.g., computer system) 600 may include a hardware processor602 (e.g., a central processing unit (CPU), a graphics processing unit(GPU), a hardware processor core, or any combination thereof), a mainmemory 604 and a static memory 606, some or all of which may communicatewith each other via an interlink (e.g., bus) 608. The machine 600 mayfurther include a power management device 632, a graphics display device610, an alphanumeric input device 612 (e.g., a keyboard), and a userinterface (UI) navigation device 614 (e.g., a mouse). In an example, thegraphics display device 610, alphanumeric input device 612, and UInavigation device 614 may be a touch screen display. The machine 600 mayadditionally include a storage device (i.e., drive unit) 616, a signalgeneration device 618 (e.g., a speaker), an enhanced channel soundingdevice 619, a network interface device/transceiver 620 coupled toantenna(s) 630, and one or more sensors 628, such as a globalpositioning system (GPS) sensor, a compass, an accelerometer, or othersensor. The machine 600 may include an output controller 634, such as aserial (e.g., universal serial bus (USB), parallel, or other wired orwireless (e.g., infrared (IR), near field communication (NFC), etc.)connection to communicate with or control one or more peripheral devices(e.g., a printer, a card reader, etc.)). The operations in accordancewith one or more example embodiments of the present disclosure may becarried out by a baseband processor. The baseband processor may beconfigured to generate corresponding baseband signals. The basebandprocessor may further include physical layer (PHY) and medium accesscontrol layer (MAC) circuitry, and may further interface with thehardware processor 602 for generation and processing of the basebandsignals and for controlling operations of the main memory 604, thestorage device 616, and/or the enhanced channel sounding device 619. Thebaseband processor may be provided on a single radio card, a singlechip, or an integrated circuit (IC).

The storage device 616 may include a machine readable medium 622 onwhich is stored one or more sets of data structures or instructions 624(e.g., software) embodying or utilized by any one or more of thetechniques or functions described herein. The instructions 624 may alsoreside, completely or at least partially, within the main memory 604,within the static memory 606, or within the hardware processor 602during execution thereof by the machine 600. In an example, one or anycombination of the hardware processor 602, the main memory 604, thestatic memory 606, or the storage device 616 may constitutemachine-readable media.

The enhanced channel sounding device 619 may carry out or perform any ofthe operations and processes (e.g., process 400 of FIG. 4A, process 450of FIG. 4B) described and shown above.

In one embodiment, the enhanced channel sounding device 619 may definean enhanced frame format for the UL NDP. The enhanced frame format iscompatible with the NDP frame format in the current 802.11ax standard.In particular, the enhanced frame format may use a portion of a HEsounding NDP PPDU, but the parameter fields in the HE signature-A(HE-SIG-A) field of the HE sounding NDP PPDU may be set according to aformat of a HE-SIG-A field of a HE TB PPDU. The enhanced frame formatmay use an entire channel or band like the HE sounding NDP PPDU, butmodified for an uplink format partially based on the HE sounding NDPPPDU. The enhanced channel sounding device 619 may define a HE-LTF modefor a sounding NDP, may determine a range from another device based on asounding frame, and may provide channel state information to anotherdevice.

It is understood that the above are only a subset of what the enhancedchannel sounding device 619 may be configured to perform and that otherfunctions included throughout this disclosure may also be performed bythe enhanced channel sounding device 619.

While the machine-readable medium 622 is illustrated as a single medium,the term “machine-readable medium” may include a single medium ormultiple media (e.g., a centralized or distributed database, and/orassociated caches and servers) configured to store the one or moreinstructions 624.

Various embodiments may be implemented fully or partially in softwareand/or firmware. This software and/or firmware may take the form ofinstructions contained in or on a non-transitory computer-readablestorage medium. Those instructions may then be read and executed by oneor more processors to enable performance of the operations describedherein. The instructions may be in any suitable form, such as but notlimited to source code, compiled code, interpreted code, executablecode, static code, dynamic code, and the like. Such a computer-readablemedium may include any tangible non-transitory medium for storinginformation in a form readable by one or more computers, such as but notlimited to read only memory (ROM); random access memory (RAM); magneticdisk storage media; optical storage media; a flash memory, etc.

The term “machine-readable medium” may include any medium that iscapable of storing, encoding, or carrying instructions for execution bythe machine 600 and that cause the machine 600 to perform any one ormore of the techniques of the present disclosure, or that is capable ofstoring, encoding, or carrying data structures used by or associatedwith such instructions. Non-limiting machine-readable medium examplesmay include solid-state memories and optical and magnetic media. In anexample, a massed machine-readable medium includes a machine-readablemedium with a plurality of particles having resting mass. Specificexamples of massed machine-readable media may include non-volatilememory, such as semiconductor memory devices (e.g., electricallyprogrammable read-only memory (EPROM), or electrically erasableprogrammable read-only memory (EEPROM)) and flash memory devices;magnetic disks, such as internal hard disks and removable disks;magneto-optical disks; and CD-ROM and DVD-ROM disks.

The instructions 624 may further be transmitted or received over acommunications network 626 using a transmission medium via the networkinterface device/transceiver 620 utilizing any one of a number oftransfer protocols (e.g., frame relay, internet protocol (IP),transmission control protocol (TCP), user datagram protocol (UDP),hypertext transfer protocol (HTTP), etc.). Example communicationsnetworks may include a local area network (LAN), a wide area network(WAN), a packet data network (e.g., the Internet), mobile telephonenetworks (e.g., cellular networks), plain old telephone (POTS) networks,wireless data networks (e.g., Institute of Electrical and ElectronicsEngineers (IEEE) 802.11 family of standards known as Wi-Fi®, IEEE 802.16family of standards known as WiMax®), IEEE 802.15.4 family of standards,and peer-to-peer (P2P) networks, among others. In an example, thenetwork interface device/transceiver 620 may include one or morephysical jacks (e.g., Ethernet, coaxial, or phone jacks) or one or moreantennas to connect to the communications network 626. In an example,the network interface device/transceiver 620 may include a plurality ofantennas to wirelessly communicate using at least one of single-inputmultiple-output (SIMO), multiple-input multiple-output (MIMO), ormultiple-input single-output (MISO) techniques. The term “transmissionmedium” shall be taken to include any intangible medium that is capableof storing, encoding, or carrying instructions for execution by themachine 600 and includes digital or analog communications signals orother intangible media to facilitate communication of such software. Theoperations and processes described and shown above may be carried out orperformed in any suitable order as desired in various implementations.Additionally, in certain implementations, at least a portion of theoperations may be carried out in parallel. Furthermore, in certainimplementations, less than or more than the operations described may beperformed.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any embodiment described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other embodiments. The terms “computing device,” “userdevice,” “communication station,” “station,” “handheld device,” “mobiledevice,” “wireless device” and “user equipment” (UE) as used hereinrefers to a wireless communication device such as a cellular telephone,a smartphone, a tablet, a netbook, a wireless terminal, a laptopcomputer, a femtocell, a high data rate (HDR) subscriber station, anaccess point, a printer, a point of sale device, an access terminal, orother personal communication system (PCS) device. The device may beeither mobile or stationary.

As used within this document, the term “communicate” is intended toinclude transmitting, or receiving, or both transmitting and receiving.This may be particularly useful in claims when describing theorganization of data that is being transmitted by one device andreceived by another, but only the functionality of one of those devicesis required to infringe the claim. Similarly, the bidirectional exchangeof data between two devices (both devices transmit and receive duringthe exchange) may be described as “communicating,” when only thefunctionality of one of those devices is being claimed. The term“communicating” as used herein with respect to a wireless communicationsignal includes transmitting the wireless communication signal and/orreceiving the wireless communication signal. For example, a wirelesscommunication unit, which is capable of communicating a wirelesscommunication signal, may include a wireless transmitter to transmit thewireless communication signal to at least one other wirelesscommunication unit, and/or a wireless communication receiver to receivethe wireless communication signal from at least one other wirelesscommunication unit.

As used herein, unless otherwise specified, the use of the ordinaladjectives “first,” “second,” “third,” etc., to describe a commonobject, merely indicates that different instances of like objects arebeing referred to and are not intended to imply that the objects sodescribed must be in a given sequence, either temporally, spatially, inranking, or in any other manner.

The term “access point” (AP) as used herein may be a fixed station. Anaccess point may also be referred to as an access node, a base station,an evolved node B (eNodeB), or some other similar terminology known inthe art. An access terminal may also be called a mobile station, userequipment (UE), a wireless communication device, or some other similarterminology known in the art. Embodiments disclosed herein generallypertain to wireless networks. Some embodiments may relate to wirelessnetworks that operate in accordance with one of the IEEE 802.11standards.

Some embodiments may be used in conjunction with various devices andsystems, for example, a personal computer (PC), a desktop computer, amobile computer, a laptop computer, a notebook computer, a tabletcomputer, a server computer, a handheld computer, a handheld device, apersonal digital assistant (PDA) device, a handheld PDA device, anon-board device, an off-board device, a hybrid device, a vehiculardevice, a non-vehicular device, a mobile or portable device, a consumerdevice, a non-mobile or non-portable device, a wireless communicationstation, a wireless communication device, a wireless access point (AP),a wired or wireless router, a wired or wireless modem, a video device,an audio device, an audio-video (A/V) device, a wired or wirelessnetwork, a wireless area network, a wireless video area network (WVAN),a local area network (LAN), a wireless LAN (WLAN), a personal areanetwork (PAN), a wireless PAN (WPAN), and the like.

Some embodiments may be used in conjunction with one way and/or two-wayradio communication systems, cellular radio-telephone communicationsystems, a mobile phone, a cellular telephone, a wireless telephone, apersonal communication system (PCS) device, a PDA device whichincorporates a wireless communication device, a mobile or portableglobal positioning system (GPS) device, a device which incorporates aGPS receiver or transceiver or chip, a device which incorporates an RFIDelement or chip, a multiple input multiple output (MIMO) transceiver ordevice, a single input multiple output (SIMO) transceiver or device, amultiple input single output (MISO) transceiver or device, a devicehaving one or more internal antennas and/or external antennas, digitalvideo broadcast (DVB) devices or systems, multi-standard radio devicesor systems, a wired or wireless handheld device, e.g., a smartphone, awireless application protocol (WAP) device, or the like.

Some embodiments may be used in conjunction with one or more types ofwireless communication signals and/or systems following one or morewireless communication protocols, for example, radio frequency (RF),infrared (IR), frequency-division multiplexing (FDM), orthogonal FDM(OFDM), time-division multiplexing (TDM), time-division multiple access(TDMA), extended TDMA (E-TDMA), general packet radio service (GPRS),extended GPRS, code-division multiple access (CDMA), wideband CDMA(WCDMA), CDMA 2000, single-carrier CDMA, multi-carrier CDMA,multi-carrier modulation (MDM), discrete multi-tone (DMT), Bluetooth®,global positioning system (GPS), Wi-Fi, Wi-Max, ZigBee, ultra-wideband(UWB), global system for mobile communications (GSM), 2G, 2.5G, 3G,3.5G, 4G, fifth generation (5G) mobile networks, 3GPP, long termevolution (LTE), LTE advanced, enhanced data rates for GSM Evolution(EDGE), or the like. Other embodiments may be used in various otherdevices, systems, and/or networks.

Example 1 may be a device comprising memory and processing circuitryconfigured to: cause to send a trigger frame to a group of stationdevices, the group of station devices comprising a first station device,wherein the trigger frame comprises a first indication of a highefficiency (HE) long training field (HE-LTF) mode and a secondindication of a guard interval duration; identify a HE trigger-based(TB) null data packet (NDP) received from the first station device,wherein the HE TB NDP comprises a first packet extension field, whereinthe HE TB NDP is associated with the HE-LTF mode and the guard intervalduration; determine channel information based on the HE TB NDP; andcause to send a downlink NDP, wherein the downlink NDP comprises asecond packet extension field and is associated with the HE-LTF mode andthe guard interval duration.

Example 2 may include the device of example 1 and/or some other exampleherein, wherein the HE-LTF mode is a 2x HE-LTF mode.

Example 3 may include the device of example 2 and/or some other exampleherein, wherein the guard interval duration is 0.8 microseconds.

Example 4 may include the device of example 2 and/or some other exampleherein, wherein the guard interval duration is 1.6 microseconds.

Example 5 may include the device of example 1 and/or some other exampleherein, wherein the first packet extension field is greater than zero.

Example 6 may include the device of example 1 and/or some other exampleherein, wherein the first packet extension field is 4 microseconds,wherein the HE TB NDP further comprises a first HE short training field(HE-STF), wherein the first HE-STF has a duration of 8 microseconds,wherein the downlink NDP comprises a second HE-STF, and wherein thesecond HE-STF has a duration of 4 microseconds.

Example 7 may include the device of example 1 and/or some other exampleherein, wherein the HE TB NDP comprises a set of fields, wherein thedownlink NDP comprises the set of fields, wherein the first packetextension field is the same as the second packet extension field,wherein the set of fields comprises the first packet extension field anda HE signal-A (HE-SIG-A) field, wherein a first HE-SIG-A field of the HETB NDP comprises first parameters, wherein a second HE-SIG-A field ofthe downlink NDP comprises second parameters, wherein the firstparameters are different from the second parameters.

Example 8 may include the device of example 1 and/or some other exampleherein, further comprising a transceiver configured to transmit andreceive wireless signals.

Example 9 may include the device of example 8 and/or some other exampleherein, further comprising one or more antennas coupled to thetransceiver.

Example 10 may include a non-transitory computer-readable medium storingcomputer-executable instructions which when executed by one or moreprocessors result in performing operations comprising: identifying atrigger frame received from a responding device; determining, based onthe trigger frame, a high efficiency (HE) long training field (HE-LTF)mode and a guard interval duration; determining, based on the HE-LTFmode and the guard interval duration, a HE trigger-based (TB) null datapacket (NDP), wherein the HE TB NDP comprises a first packet extensionfield; causing to send the HE TB NDP to the responding device;identifying a downlink NDP received from the responding device, whereinthe downlink NDP comprises a second packet extension field; anddetermining, based on the downlink NDP, channel state information.

Example 11 may include the non-transitory computer-readable medium ofexample 10 and/or some other example herein, wherein the HE-LTF mode isa 2x HE-LTF mode.

Example 12 may include the non-transitory computer-readable medium ofexample 10 and/or some other example herein, wherein the guard intervalduration is 0.8 microseconds.

Example 13 may include the non-transitory computer-readable medium ofexample 10 and/or some other example herein, wherein the guard intervalduration is 1.6 microseconds.

Example 14 may include the non-transitory computer-readable medium ofexample 10 and/or some other example herein, wherein the first packetextension field is greater than zero.

Example 15 may include the non-transitory computer-readable medium ofexample 10 and/or some other example herein, wherein the first packetextension field has a duration of 4 microseconds, wherein the HE TB NDPfurther comprises a first HE short training field (HE-STF), wherein thefirst HE-STF has a duration of 8 microseconds, wherein the downlink NDPcomprises a second HE-STF, and wherein the second HE-STF has a durationof 4 microseconds.

Example 16 may include the non-transitory computer-readable medium ofexample 10 and/or some other example herein, wherein the HE TB NDPcomprises a set of fields, wherein the downlink NDP is a HE soundingNDP, wherein the downlink HE sounding NDP comprises the set of fields,wherein the first packet extension field is the same as the secondpacket extension field, wherein the set of fields comprises the firstpacket extension field and a HE signal-A (HE-SIG-A) field, wherein afirst HE-SIG-A field of the HE TB NDP comprises first parameters,wherein a second HE-SIG-A field of the downlink HE sounding NDPcomprises second parameters, wherein the first parameters are differentfrom the second parameters.

Example 17 may include a method comprising: causing to send, by aninitiator device, a null data packet announcement (NDPA) frame to aresponder device; determining, by the initiator device, an uplink nulldata packet (NDP), wherein the uplink NDP comprises a first indicationof a high efficiency (HE) long training field (HE-LTF) mode, a secondindication of a guard interval duration, and a first packet extensionfield; causing to send, by the initiator device, the uplink NDP to theresponder device; identifying, by the initiator device, an downlink NDPreceived from the responder device, wherein the downlink NDP comprises asecond packet extension field and a HE signal-A1 (HE-SIG-A1) field,wherein the downlink NDP is associated with the HE-LTF mode and theguard interval duration indicated in the HE-SIG-A1 field; anddetermining, by the initiator device, channel state information based onthe downlink NDP received from the responder device.

Example 18 may include the method of example 17 and/or some otherexample herein, wherein the uplink NDP is a first HE sounding NDP frame,and wherein the downlink NDP is a second HE sounding NDP frame.

Example 19 may include the method of example 17 and/or some otherexample herein, wherein the HE-LTF mode is a 2x HE-LTF mode.

Example, 20 may include the method of example 17 and/or some otherexample herein, wherein the guard interval duration is 0.8 microsecondsor 1.6 microseconds, wherein the first packet extension field has aduration of 4 microseconds, wherein the second packet extension fieldhas a duration of 4 microseconds, and wherein a first bit of theHE-SIG-A1 field of the downlink NDP is set to zero to indicate that thedownlink NDP is a HE trigger-based data unit.

Example 21 may include an apparatus comprising means for: causing tosend a null data packet announcement (NDPA) frame to a responder device;determining an uplink null data packet (NDP), wherein the uplink NDPcomprises a first indication of a high efficiency (HE) long trainingfield (HE-LTF) mode, a second indication of a guard interval duration,and a first packet extension field; causing to send the uplink NDP tothe responder device; identifying an downlink NDP received from theresponder device, wherein the downlink NDP comprises a second packetextension field and a HE signal-A1 (HE-SIG-A1) field, wherein thedownlink NDP is associated with the HE-LTF mode and the guard intervalduration indicated in the HE-SIG-A1 field; and determining channel stateinformation based on the downlink NDP received from the responderdevice.

Example 22 may include one or more non-transitory computer-readablemedia comprising instructions to cause an electronic device, uponexecution of the instructions by one or more processors of theelectronic device, to perform one or more elements of a method describedin or related to any of examples 1-21, or any other method or processdescribed herein

Example 23 may include an apparatus comprising logic, modules, and/orcircuitry to perform one or more elements of a method described in orrelated to any of examples 1-21, or any other method or processdescribed herein.

Example 24 may include a method, technique, or process as described inor related to any of examples 1-21 or portions or parts thereof.

Example 25 may include an apparatus comprising: one or more processorsand one or more computer readable media comprising instructions that,when executed by the one or more processors, cause the one or moreprocessors to perform the method, techniques, or process as described inor related to any of examples 1-21, or portions thereof.

Example 26 may include a method of communicating in a wireless networkas shown and described herein.

Example 27 may include a system for providing wireless communication asshown and described herein.

Example 28 may include a device for providing wireless communication asshown and described herein.

Embodiments according to the disclosure are in particular disclosed inthe attached claims directed to a method, a storage medium, a device anda computer program product, wherein any feature mentioned in one claimcategory, e.g., method, can be claimed in another claim category, e.g.,system, as well. The dependencies or references back in the attachedclaims are chosen for formal reasons only. However, any subject matterresulting from a deliberate reference back to any previous claims (inparticular multiple dependencies) can be claimed as well, so that anycombination of claims and the features thereof are disclosed and can beclaimed regardless of the dependencies chosen in the attached claims.The subject-matter which can be claimed comprises not only thecombinations of features as set out in the attached claims but also anyother combination of features in the claims, wherein each featurementioned in the claims can be combined with any other feature orcombination of other features in the claims. Furthermore, any of theembodiments and features described or depicted herein can be claimed ina separate claim and/or in any combination with any embodiment orfeature described or depicted herein or with any of the features of theattached claims.

The foregoing description of one or more implementations providesillustration and description, but is not intended to be exhaustive or tolimit the scope of embodiments to the precise form disclosed.Modifications and variations are possible in light of the aboveteachings or may be acquired from practice of various embodiments.

Certain aspects of the disclosure are described above with reference toblock and flow diagrams of systems, methods, apparatuses, and/orcomputer program products according to various implementations. It willbe understood that one or more blocks of the block diagrams and flowdiagrams, and combinations of blocks in the block diagrams and the flowdiagrams, respectively, may be implemented by computer-executableprogram instructions. Likewise, some blocks of the block diagrams andflow diagrams may not necessarily need to be performed in the orderpresented, or may not necessarily need to be performed at all, accordingto some implementations.

These computer-executable program instructions may be loaded onto aspecial-purpose computer or other particular machine, a processor, orother programmable data processing apparatus to produce a particularmachine, such that the instructions that execute on the computer,processor, or other programmable data processing apparatus create meansfor implementing one or more functions specified in the flow diagramblock or blocks. These computer program instructions may also be storedin a computer-readable storage media or memory that may direct acomputer or other programmable data processing apparatus to function ina particular manner, such that the instructions stored in thecomputer-readable storage media produce an article of manufactureincluding instruction means that implement one or more functionsspecified in the flow diagram block or blocks. As an example, certainimplementations may provide for a computer program product, comprising acomputer-readable storage medium having a computer-readable program codeor program instructions implemented therein, said computer-readableprogram code adapted to be executed to implement one or more functionsspecified in the flow diagram block or blocks. The computer programinstructions may also be loaded onto a computer or other programmabledata processing apparatus to cause a series of operational elements orsteps to be performed on the computer or other programmable apparatus toproduce a computer-implemented process such that the instructions thatexecute on the computer or other programmable apparatus provide elementsor steps for implementing the functions specified in the flow diagramblock or blocks.

Accordingly, blocks of the block diagrams and flow diagrams supportcombinations of means for performing the specified functions,combinations of elements or steps for performing the specified functionsand program instruction means for performing the specified functions. Itwill also be understood that each block of the block diagrams and flowdiagrams, and combinations of blocks in the block diagrams and flowdiagrams, may be implemented by special-purpose, hardware-based computersystems that perform the specified functions, elements or steps, orcombinations of special-purpose hardware and computer instructions.

Conditional language, such as, among others, “can,” “could,” “might,” or“may,” unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainimplementations could include, while other implementations do notinclude, certain features, elements, and/or operations. Thus, suchconditional language is not generally intended to imply that features,elements, and/or operations are in any way required for one or moreimplementations or that one or more implementations necessarily includelogic for deciding, with or without user input or prompting, whetherthese features, elements, and/or operations are included or are to beperformed in any particular implementation.

Many modifications and other implementations of the disclosure set forthherein will be apparent having the benefit of the teachings presented inthe foregoing descriptions and the associated drawings. Therefore, it isto be understood that the disclosure is not to be limited to thespecific implementations disclosed and that modifications and otherimplementations are intended to be included within the scope of theappended claims. Although specific terms are employed herein, they areused in a generic and descriptive sense only and not for purposes oflimitation.

What is claimed is:
 1. A device, the device comprising processingcircuitry coupled to storage, the processing circuitry configured to:send a trigger frame to one or more initiator devices to solicit uplinksounding null data packet (NDP) feedbacks identify a first HEtrigger-based (TB) NDP feedback received from a first initiator device,wherein the HE TB NDP feedback comprises a first packet extension fieldand does not contain a data field, wherein the HE TB NDP has a supportedHE-LTF mode of 2x HE-LTF with a 1.6 microseconds guard intervalduration; and send a null data packet announcement (NDPA) to the one ormore initiator devices.
 2. The device of claim 1, wherein the NDPA isfollowed by one or more downlink NDPs to the one or more initiatordevices.
 3. The device of claim 2, wherein the one or more downlink NDPsare followed by a measurement report frame sent to the one or moreinitiator devices.
 4. The device of claim 2, wherein the NDPA is sentafter a passage of a short inter-frame space (SIFS) from receiving alast NDP from the one or more initiator devices.
 5. The device of claim2, wherein the HE TB NDP only supports the HE-LTF mode of 2x HE-LTF withthe 1.6 microseconds guard interval duration.
 6. The device of claim 1,wherein the processing circuitry is further configured to identify asecond HE TB NDP feedback received from a second initiator device,wherein the second HE TB NDP feedback comprises a second packetextension field and does not contain a data field, wherein the second HETB NDP has a supported HE-LTF mode of 2x HE-LTF with a 1.6 microsecondsguard interval duration.
 7. The device of claim 1, wherein the firstpacket extension field is 4 microseconds, wherein the HE TB NDP furthercomprises a first sounding HE short training field (HE-STF), wherein thefirst sounding HE-STF included in the HE TB NDP has a duration of 8microseconds for sounding.
 8. The device of claim 1, further comprisinga transceiver configured to transmit and receive wireless signals. 9.The device of claim 8, further comprising an antenna coupled to thetransceiver to cause to send the trigger frame.
 10. A non-transitorycomputer-readable medium storing computer-executable instructions whichwhen executed by one or more processors result in performing operationscomprising: sending a trigger frame to one or more initiator devices tosolicit uplink sounding null data packet (NDP) feedbacks identifying afirst HE trigger-based (TB) NDP feedback received from a first initiatordevice, wherein the HE TB NDP feedback comprises a first packetextension field and does not contain a data field, wherein the HE TB NDPhas a supported HE-LTF mode of 2x HE-LTF with a 1.6 microseconds guardinterval duration; and sending a null data packet announcement (NDPA) tothe one or more initiator devices.
 11. The non-transitorycomputer-readable medium of claim 10, wherein the NDPA is followed byone or more downlink NDPs to the one or more initiator devices.
 12. Thenon-transitory computer-readable medium of claim 11, wherein the one ormore downlink NDPs are followed by a measurement report frame sent tothe one or more initiator devices.
 13. The non-transitorycomputer-readable medium of claim 11, wherein the NDPA is sent after apassage of a short inter-frame space (SIFS) from receiving a last NDPfrom the one or more initiator devices.
 14. The non-transitorycomputer-readable medium of claim 11, wherein the HE TB NDP onlysupports the HE-LTF mode of 2x HE-LTF with the 1.6 microseconds guardinterval duration.
 15. The non-transitory computer-readable medium ofclaim 10, wherein the operations further comprise identifying a secondHE TB NDP feedback received from a second initiator device, wherein thesecond HE TB NDP feedback comprises a second packet extension field anddoes not contain a data field, wherein the second HE TB NDP has asupported HE-LTF mode of 2x HE-LTF with a 1.6 microseconds guardinterval duration.
 16. The non-transitory computer-readable medium ofclaim 10, wherein the first packet extension field is 4 microseconds,wherein the HE TB NDP further comprises a first sounding HE shorttraining field (HE-STF), wherein the first sounding HE-STF included inthe HE TB NDP has a duration of 8 microseconds for sounding.
 17. Amethod comprising: sending a trigger frame to one or more initiatordevices to solicit uplink sounding null data packet (NDP) feedbacksidentifying a first HE trigger-based (TB) NDP feedback received from afirst initiator device, wherein the HE TB NDP feedback comprises a firstpacket extension field and does not contain a data field, wherein the HETB NDP has a supported HE-LTF mode of 2x HE-LTF with a 1.6 microsecondsguard interval duration; and sending a null data packet announcement(NDPA) to the one or more initiator devices.
 18. The method of claim 17,wherein the NDPA is followed by one or more downlink NDPs to the one ormore initiator devices.
 19. The method of claim 18, wherein the one ormore downlink NDPs are followed by a measurement report frame sent tothe one or more initiator devices.
 20. The method of claim 18, whereinthe NDPA is sent after a passage of a short inter-frame space (SIFS)from receiving a last NDP from the one or more initiator devices.